Envelope for encapsulating XML data
  - Definition of an XML envelope: outermost construct of the XMLP
  message.
 
  - One-way message: sender, receiver, intermediary along the message
  path.
 
  - Extensibility:
    
      - Envelope defines the core structure.
 
      - The protocol can be extended with some XMLP modules:
        
          - XMLP blocks: syntactic construct.
 
          - XMLP handler: abstraction for the processing of the
          module(s).
 
        
       
    
   
